Convergent effects of different anesthetics on changes in phase alignment of cortical oscillations.

Two anesthetics with different molecular actions, ketamine and dexmedetomidine, both increase phase locking of neural oscillations in the prefrontal cortex of nonhuman primates during loss of responsiveness. Within a hemisphere, neighboring prefrontal subregions become less phase-aligned, possibly due to large traveling waves. However, homologous areas across hemispheres become more aligned in phase. These distinct patterns of cortical phase alignment, markedly different from waking states, may represent a common mechanism by which diverse anesthetics produce loss of responsiveness.

Study at a glance

Abstract

Many anesthetics cause loss of consciousness despite having diverse underlying molecular and circuit actions. To explore the convergent effects of these drugs, we examine how anesthetic doses of ketamine and dexmedetomidine affect bilateral oscillations in the prefrontal cortex of nonhuman primates. Both anesthetics increase phase locking in the ventrolateral and dorsolateral prefrontal cortex, within and across hemispheres. However, the nature of the phase locking varies. Neighboring prefrontal subregions within a hemisphere show decreased phase alignment with both drugs. Local analyses within a region suggest that this finding could be explained by broad cortical distance-based effects, such as large traveling waves. In contrast, homologous areas across hemispheres become more aligned in phase. Our results suggest that both anesthetics induce strong patterns of cortical phase alignment that are markedly different from those during waking and that these patterns may be a common feature driving loss of responsiveness from different anesthetic drugs.